Electrophotographic imaging apparatus and methods are well known in the art. Coriventional electrophotographic imaging apparatus, often called xe2x80x9cprinters,xe2x80x9d typically include, among other components, an image forming device, a fusing device (xe2x80x9cfuserxe2x80x9d), a toner applicator, and media conveyance system. The image-forming device typically includes both a photoconductive surface and a selectively controllable light source. The light source typically includes either an array of light emitting diodes, or a laser and associated laser scanning mechanism. The photoconductive surface is generally in the form of either an endless rotatable drum, or an endless circulatable belt.
During operation of conventional imaging apparatus, the photoconductive surface is generally rotated or circulated so as to continually move relative to the light source. The light source is directed at the photoconductive surface and is capable of selectively exposing predetermined areas of the photoconductive surface on a pixel-by-pixel basis. That is, as the photoconductive surface moves relative to the light source, the light source is selectively pulsed in accordance with predetermined data. This selective exposure of the photoconductive surface to the light source results in the formation of a latent electrostatic image on the photoconductive surface.
After the latent electrostatic image is formed on the photoconductive surface, the toner applicator applies one or more toners to the photoconductive surface to form a visible image. In a xe2x80x9cblack-and-whitexe2x80x9d printer, only black toner is generally applied to the photoconductive surface, while in xe2x80x9ccolorxe2x80x9d printers, one or more different colors of toner is applied. The visible image is then transferred from the photoconductive surface to a carrier media such as a sheet of paper or the like.
After receiving the toner from the photoconductive surface, the media is then moved and guided by the media conveyance system to the fusing device. The fusing device typically includes a xe2x80x9chot rollerxe2x80x9d and an associated pressure roller that are oriented relative to one another so as to form a nip point there between. The hot roller typically includes a heating element that is generally controlled so as to maintain a substantially constant temperature. After receiving the toner in the form of an image, the sheet of media is passed through the nip point between the rollers of the fixing device, whereby the media and the toner thereon are heated so as to bond, or xe2x80x9cfix,xe2x80x9d the toner to the media. The hot roller and pressure roller generally rotate at a substantially constant rotational speed.
The amount of heat transferred to the media and toner supported thereon during the image fixing process is generally known to be relatively critical. That is, if too much heat is applied to the media during the image fixing process, the media can become curled as a result. On the other hand, if not enough heat is transferred to the media during the image fixing process, the toner is not completely bonded to the media and thus can become easily smeared, and/or can peel off of the media.
As mentioned above, typical prior art fixing devices are often equipped with a temperature control system that is configured to substantially maintain the temperature of the hot roller at a set, predetermined level. Such temperature control systems typically include a temperature sensor and a control system. The temperature sensor is configured to detect the temperature of the hot roller and/or the pressure roller, and the control system is configured to adjust the amount of energy supplied to the heating element within the hot roller in response to the temperature detected by the temperature sensor.
For example, if the temperature of the hot roller and/or the pressure roller is detected by the sensor to be below the set temperature point, then the control system increases -the amount of energy supplied to the heating element in an attempt to increase the temperature of the hot roller so as to approach the set point. Conversely, if the temperature of the hot roller and/or the pressure roller is detected by the sensor to be above the set temperature point, then the control system decreases or shuts off, the energy supplied to the heating element in an attempt to decrease the temperature of the hot roller accordingly. The temperature set point is generally determined to provide the best overall fuser performance over a given range of possible variable conditions. Such conditions include media surface roughness, media temperature, media thickness, and media moisture content, as well as ambient environmental conditions.
In accordance with various embodiments of the present invention, a method for controlling the operation of a fusing device in an electrophotbgraphic imaging apparatus includes providing a fusing device, the operation of which is characterized by a fusing temperature, a fusing speed, and a fusing pressure. The method can include controlling the fusing speed as a function of the fusing temperature, controlling the fusing pressure as a function of the fusing speed, and controlling the fusing temperature as a function of the fusing speed and the fusing pressure. An apparatus in accordance with at least one embodiment of the present invention can include at least one signal source that is configured to transmit associated data indicative of an operating parameter. The apparatus can also include a processor that is configured to receive the data transmitted from the signal source and to control the fusing speed as a function of the data. The processor can also be configured to control the fusing temperature as well as the fusing pressure as respective functions of the data.